Jump to content
HybridZ

Home Made Control Arms


Recommended Posts

  • 2 weeks later...
  • Replies 65
  • Created
  • Last Reply

Top Posters In This Topic

I finally finished the rear arms. I tiged everything using ER70S-2 filler rod and it came out pretty good. The chrome-moly was a really easy to weld.

 

I did a test install, (i'll have pics when their painted) which only took a couple minutes, and right away I could tell there was less bind because I could actually push up on the suspension unlike before.

 

I compared the weight to the stock flimzy arms and my new tubed ones came in 1.6 lbs less. Not much, but the stiffness gained is what counts. In fact, when I had the stock arm on the jig I could actually bend the mounting points in almost every direction, by hand!

 

Total spent on rear arms: $219.22

Time spent: Too much!

 

IMG_1289.JPG

 

IMG_12951.JPG

 

IMG_13201.JPG

 

IMG_1322.JPG

Link to comment
Share on other sites

Thanks guys.

 

I actually considered making a few sets, but I just don't have the proper tools to do the job efficiently. In fact the tools I used were; hand drill, angle grinder/cutoff wheel/wire brush, hacksaw, and I used the TIG welder at my school. I'd love to reproduce these but unfourtunatly I can't.

 

I used this http://www.metalgeek.com/cgi-system/php5.cgi/static/cope.pcgi to make the notches on the tubes. Just plug in the tube sizes, angle then print, cut, tape, draw, notch!

Link to comment
Share on other sites

Those look great! When I get around to making my next set, they will be similarly constructed. The only thing that I plan to do differently is make the rear heim the solid point, and let the front heim be the toe adjuster.

 

What wall tubing did you end up with?

 

My current control arms are made using 1.125 x 0.058 4130 tubing, but they use a lot of extra triangulation for redundancy.

 

With your new control arms you have converted the rear suspension from an H-arm to an A-arm toe link type strut. By doing so, you have given youself more freedom regarding toe and caster.

 

The H-arm type strut suspension demands that the strut is perpendicular to the control arm. If the strut isn't perpendicular, the control arm and strut must flex or bind as the suspension goes through its range of motion. Because of the requirement for an H-arm strut to be always perpendicular to the control arm, caster and toe are limited.

 

The A-arm type gives you more options. You can now move the top of the strut forward or aft. As the suspension moves through its range of motion, the toe link rotate to prevent the suspension from binding. Moving the top of the strut forward or aft will allow you to play with anti-squat and roll steer of the rear suspension.

Link to comment
Share on other sites

Painted and installed:

 

IMG_1325.JPG

 

IMG_13261.JPG

 

IMG_1329.JPG

 

IMG_13501.JPG

 

Another plus with these arms is that now I can lengthen the travel of my axles ( lowered 240Z W/ R200 = little axle travel esp. on driver side) when adjusting camber by extending the arms outward. Maybe I don't need to switch to cv's after all!

Link to comment
Share on other sites

Very nicely done Myron. Be careful adjusting the track width too much though. You want no more exposed thread than is absolutely necessary on those rod ends. The rule of thumb is 1.5x the thread diameter, which on a typical 5/8" rod end means that you can move them out 5/16".

 

If you wanted to make the arms significantly longer the thing to do would be to move the tube out that holds the rod end or make the triangle bigger, then use a longer turnbuckle in back.

Link to comment
Share on other sites

those front control arms make me piss my pants just thinking about my car coming down on the front after lifting the front wheels of the ground out of the whole! i guess they would be more suited for a 6 cylinder car and autocross vs turbo sbc and at the drag strip.:icon52:

Link to comment
Share on other sites

Myron: Have you finished the fixture to build rear control arms. If so it would be nice to send a deposit and have you send the fixture so that I can make a set of rear control arms made of Chrome-Moly Tubing.

 

 

Sure your welcome to use it just PM me.

Link to comment
Share on other sites

  • 2 weeks later...

Having run similar arms on the back of a V8 powered car with wide slicks (FA) we've found that the toe-link rod ends need to be very high quality. The slot gap (speedway, jegs, summit QA-1 parts) wore out in about 6 events. These were the 5/8 best quality with kevlar liners.

 

These parts have been switched to Aurora 3-piece rod ends in a higher spec. I'll report back how these do once we have more mileage. But for anyone looking to use this in competition (or possible extreme street use) please keep in mind the rod end requirements. Another option would be to convert to 3/4 rod ends to gain bearing surface area.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...